Hadith: One of you bites his brother like a male camel does! There is no blood money for you.

عن عمران بن حصين رضي الله عنهما «أن رجلا عَضَّ يَدَ رجل؛ فَنَزَعَ يَدَهُ من فِيهِ؛ فوقعت ثَنِيَّتُهُ؛ فاختصما إلى النبي صلى الله عليه وسلم فقال: يَعَضُّ أحدُكم أخاه كما يَعَضُّ الفَحْلُ؛ لا دِيَةَ لك».
[صحيح] - [متفق عليه]

‘Imrān ibn Husayn (may Allah be pleased with him) reported: A man bit another man's hand, so the latter pulled his hand out of his mouth by force, causing two of the former's incisors to fall out. They referred their dispute to the Prophet (may Allah's peace and blessings be upon him), who said: "One of you bites his brother like a male camel does! There is no blood money for you."
Sahih/Authentic. - [Al-Bukhari and Muslim]

Explanation

A man attacked another man and bit his hand. The one who was bitten pulled his hand by force from the other man's mouth, causing his two incisors to fall out. They submitted their case to the Prophet (may Allah's peace and blessings be upon him). The one who bit the man's hand was claiming blood money for his two teeth that fell out, whereas the other man defended himself saying that he only wanted to save his hand from the other man's teeth. The Prophet (may Allah's peace and blessings be upon him) refuted the claim of the former and expressed his discontent at what he had done, likening that to the attitude of fierce animals. He said: "One of you bites his brother like a male camel does! There is no blood money for you." Because the one who starts is the aggressor.